rushing to the bookstore?

I remember when I was in college, many students used to rush to sell textbooks before even giving the exam at the end of the term. The reason being that if the store got too many of the textbooks back, it wouldn't want yours, so there was always a rush to sell them and get some money in time for the Christmas holidays. The same went for the Spring semester, but it wasn't that much of a dash since most students were going to get jobs anyway.